The U.S. Department of Justice is seeking to revoke the citizenship of an 86-year-old Bellevue man and former restaurant host who, investigators say, worked with a Nazi mobile killing unit that murdered thousands of Jews, Gypsies and political dissidents during World War II.

Peter Egner was part of an infamous Nazi SS unit working in German-occupied Serbia from April 1941 to September 1943, according to a complaint filed in U.S. District Court in Seattle.

Reached by telephone at his retirement center home, Egner confirmed his identity to The Associated Press, but said he was unaware of the complaint.

Asked about his alleged service with the Nazis, he said: "I have no idea what you're talking about. I'm sorry. Bye."

Egner admitted in a February 2007 interview with federal officials that during his service in the mobile killing unit called Einsatzgruppe, he guarded prisoners being transferred to a concentration camp and mass grave site, according to the complaint.

Einsatzgruppe forced victims into a van in which men, women and children were gassed with carbon monoxide on their way to burial pits at Avala, outside Belgrade, the complaint continues.

...The government alleges that Peter Egner served in a notorious Nazi unit that murdered thousands of Serbian Jews and other unarmed civilians, said Office of Special Investigations Director Eli Rosenbaum, in a statement released by the Justice Department....

...No one who participated, as we allege the defendant did, in the diabolical Nazi program of persecution is entitled to retain U.S. citizenship....

Rosenbaum, 53, is among the nation's best-known and most prolific hunters of Nazi war criminals. At present, his office is seeking to strip another 14 suspected Nazis of their U.S. citizenship.

In seeking to do the same to Egner, the Justice Department has charged him with lying about his past on an application for naturalization. The government also charges Egner with lack of attachment to constitutional principles and lack of good moral character -- allegations that, if known at the time of his application, would have made him ineligible to become a U.S. citizen.

According to the federal complaint, Egner entered the country in 1960, and was naturalized in 1966. When questioned about prior military service, Egner apparently omitted his SS involvement, noting only that he had been a sergeant in the German army.

...The Nazi unit in which Peter Egner is alleged to have participated was responsible for countless deaths and unimaginable human suffering, said Acting Assistant Attorney General Matthew Friedrich in a statement released Tuesday. "By bringing this action today, we again declare our unwavering commitment to the principle that participants in Nazi crimes should not be afforded the rights and privileges of U.S. citizenship."...

Egner's immigration attorney, Robert Gibbs, said his client denies participating in any persecution. The complaint did not allege that Egner himself tortured or killed anyone, and did not make reference to how many times he might have transported prisoners or interpreted during interrogations, Gibbs noted.

...I don't think he was involved at the level that would allow them to take away his citizenship, Gibbs said. "He's been in the U.S. for almost 50 years now, and no one has anything bad to say about his time here."...

While some have questioned the continued zeal for hunting and prosecuting surviving Nazi soldiers -- most of whom are now well into their 80s -- Rabbi Marvin Hier, founder and dean of the Simon Wiesenthal Center in Los Angeles, was unapologetic.

...Why go after a person who's 86? For the simple reason that there's no time limit when it comes to crimes against humanity, he said. "What they did from 9 to 5 every day before they sat down to dinner was murder innocent people. Every day, that was their full-time job. If you're a mass murderer and you've killed hundreds or thousands of people, and you're clever enough to hide out, you should be given a reprieve -- a free pass -- just because you're 86?"...

At Silver Glen, the retirement community in Bellevue where Egner now resides, several residents described the octogenarian as a private but reliable neighbor.

None said they knew anything about his wartime activities or the charges against him.

...He's a conscientious person who respects your privacy and expects you to respect his, said resident Robert Withrow....

A chain hanging on the doorknob outside Egner's second-floor apartment indicated that he was not home Tuesday afternoon.

"Peter's probably heard about all this and staying with his daughters," Withrow said.

Sue Sampson, who lives a few doors down the hall, said she had been unaware that her neighbor was even a veteran. "We've had dinner a few times and he seems like a nice man," she said. "I don't know anything about his past."

Gibbs said Egner worked for many years as a food and beverage manager at the Olympic Hotel in Seattle.

Egner and his wife, Gerda, lived in a condominium in West Linn, Ore., from 1981 to 2006, according to former neighbor Ann Johnson. She called Egner a "loving family man" who'd worked as a maitre d' in downtown Portland.

"He was concerned about other people," Johnson said. "When my husband died a few years ago, he came to the door to offer his condolences personally and was very thoughtful."

Gerda Egner's death in 2005 left the elderly man "grief-stricken," according to Johnson. He moved to Bellevue to be closer to relatives the following year.

It is likely that Rosenbaum and his team of investigators were on Egner's trail even then. It typically takes them years to track surviving Nazis. In one instance, Rosenbaum worked a decade before finding his man.

...You know that television show 'Cold Case?' By our standards, those cases are boiling hot, he has said. "It's hard enough to prove in court a mugging that took place down the street a week ago. Imagine what it's like proving cases that took place half a century ago."...

Since the OSI began its work in 1979, it has won 107 such cases and lost six.

The rabbi for Temple B'nai Torah in Bellevue called the news about Egner "shocking."

...People have to be held responsible for their crimes. When someone commits a murder, no matter how many years ago, they should held accountable for it, said Rabbi Jim Mirel....

Aaron Breitbart, senior researcher at the Nazi-hunting Wiesenthal Center, said Nazis murdered 90 percent of Serbia's 16,000 Jews during World War II. In all, Egner's unit is believed responsible for slaughtering 17,000 civilians.

...But when the Nazis realized that they wouldn't be able to deport the Jews as quickly as they planned, they came up with another solution: the gas vans....

Breitbart characterized Egner as "a cog in the machinery" of genocide. "But the mass murder could not have taken place without these cogs in the machinery. They were essential to the 'Final Solution.' "

It's unclear whether Egner will be deported to Serbia to face criminal charges if he loses his citizenship. But the experience of John Demjanjuk, a former Cleveland auto worker accused of being the Nazi death camp guard dubbed "Ivan the Terrible, may hint at Egner's fate.

Demjanjuk was stripped of his citizenship in 1981, extradited to Israel in 1986, and sentenced to death two years later.

Israel returned him to the United States in 1993, however, after the Israeli Supreme Court ruled there was evidence showing that Demjanjuk was not Ivan the Terrible. The case is still in litigation and Demjanjuk remains in the U.S.

P-I reporters Casey McNerthney and Claire Traegeser contributed to this report, which contains information from The Associated Press. P-I reporter Paul Shukovsky can be reached at 206-448-8072 or paulshukovsky@seattlepi.com.